Why Do Women Outlive Men? WaPo: Redundancy of XX vs XY Genetics

[GreatGazoo]

The most sweeping analysis to date was released on Thursday, Oct 1 which highlighted the contrast between human and bird life expectancy trends:

We analyzed adult life expectancy in 528 mammal and 648 bird species in zoos. Like humans, 72% of mammals exhibited a female life expectancy advantage, while 68% of birds showed a male advantage, as expected from the harmful effects of sex chromosomes described by the heterogametic sex hypothesis....For example, in populations in the wild, female moose (Alces alces) have twice the adult median life span of males

However:

In birds, 25 of the 31 orders showed an overall male ALE advantage, including all well-represented orders such as galliforms (Galliformes, 9%), pigeons and doves (Columbiformes, 9%), songbirds (Passeriformes, 5%), parrots (Psittaciformes, 5%), and waterfowl (Anseriformes, 3%).

https://www.science.org/doi/10.1126/sciadv.ady8433#sec-2


WaPo summarized:

Women tend to live longer than men. There are traditional explanations: Men smoke more. They drink more. They tend to engage in riskier behavior. But the fact that this lifespan gap holds true regardless of country or century indicates something deeper is also at play.

A growing body of evidence suggests that women's relative longevity may derive, in part, from having double X chromosomes, a redundancy that protects them against harmful mutations. That theory was further bolstered Wednesday with the publication of the most sweeping analysis to date of the lifespan differences between males and females in more than 1,000 mammal and bird species...

If a baby has a pair of X chromosomes, she's a girl. If the baby inherits an X chromosome and a Y chromosome, he's a boy. In birds, however, the situation is reversed. Female birds have a pair of unlike sex chromosomes while males have the like pair... For their study, Colchero, Staerk and their colleagues collected data on the lifespans of 528 mammal species and 648 bird species kept in zoos. The team found that most other mammals are like humans, with the females of nearly three-fourths of mammal species outliving their male counterparts. But in birds, 68 percent of species studied showed a bias toward male longevity, as expected from their chromosomal makeup.

https://www.msn.com/en-us/news/technology/why-do-women-outlive-men-a-study-of-1176-species-points-to-an-answer/ar-AA1NGK38